化學摩爾問題 (急!!!!!!!!!!!!!!!!)

Question

13.07g水合碳酸鈉Na2CO3‧nH2O在強烈加熱下會生成8.23g水。

求n的值。

Answer 1

Na2CO3‧nH2O(s) → Na2CO3(s) + nH2O(l)
Molar mass of water, H2O
= (1.0 X 2 + 16.0)
= 18.0 g /mol
Number of mole of water
= Mass / Molar mass
= 8.23 / 18.0
= 0.457 mol
Mass of sodium carbonate, Na2CO3
= 13.07 - 8.23
= 4.84 g
Molar mass of sodium carbonate, Na2CO3
= 23.1 X 2 + 12.0 + 16.0 X 3
= 106.2 g / mol
Number of mole of sodium carbonate, Na2CO3
= Mass / Molar mass
= 4.84 / 106.2
= 0.0456 mol
Mole ratio of water : sodium carbonate
= 0.457 : 0.0456
= 1:10
So, n = 10

2007-01-12 20:42:16 補充：
Sorry, should beMole ratio of water : sodium carbonate= 0.457 : 0.0456= 10:1

Answer 2

8.23g氷=8.23/18=0.4572摩薾
Na2CO3的質量=13.07-8.23=4.84g
4.84g Na2CO3 = 4.84 / (23X2+12+16X3)=0.04566摩薾
n=0.4572/0.04566=10